Pianoforte.



3 mxfsmm B. BERDUX.

'PIANOFORTE.

APPLICATION FILED 811F130 1909.

983,529. Patented'Feb. 7', 1911.

2 SHEETS-SHEET 1.

THE NORRIS PETERS cu, WASHINGTON, n. c.

E. BERDUX.

PIANOFORTE.

APPLIOATIQN FILED SEPT. 30, 1909. 983,529. Patented Feb.7, 1911.

. A I; a 1 5 J .x 7; 1 j l Z- lull- 'II llll UNITED STATES PATENT OFFICE.

EMIL BERDUX, 0F MUNICH, GERMANY, ASSIGNOR- TO THE FIRM 01-? V. IBERDUX, OF MUNICH, GERMANY.

PIANOFORTE.

To all whom it may concern:

Be it known that I, Earn BnnnUX, a subject of the German Emperor, residing at Munich, Germany, have invented certain new and useful Improvements in Piano fortes, of which the following is a specification.

My invention relates to improvei'nents in pianofortes, and has especial reference to means for so improving the structure and combination of the brace bars on the string plate and sounding-board bridge that the resistance of the frame will be increased, thus obviating its tendency to bend under stress.

The principal object of my invention is to provide a construction of pianotorte in which the tone will. be of the highest quality and the structure such that bending of the frame is iractically impossible under the severe strains put upon it by the strings.

In carrying my invention into practice I groove or cut away a portion of certain of? the brace bars so that the bridge of the sounding board may pass through the groove in the brace bar, and I insert through a bore in the bridge, without touch ing the latter, a member which may either be secured to the brace-bar or form an in l'egral part thereof. The brace bars are preferably provided with strengthening ribs to Ollll 'wllSiltlt. for any loss ojt rigidity which may be occasioned by grooving the same, and the member passes through the neutral axis of the bridge so that the latter is not weakened. I thus, in fact, strengthen the frame and increase its resistance under the strain of the tensioned strings, thereby improving the tone of the instrument.

The invention is illustratively exemplified in the accompanying drawing, wherein- Figure 1 is a plan view of a portion of a pianoforte provided with my invention; Fig. 2 is a cross sectional view on the line i i-13 of Fig. 1; and Fig. is a cross sec tional view of a modified form of the invention.

Referring by reterence characters to the drawing, and particularly to Figs. 1 and 2 thereof, a designates suitably formed brace bars on the string plate some of which are preferably provided with strengthening ribs 7L. Certain of the brace bars are grooved. or cut away at F) to permit the bridge 0 of the sounding board 8 to pass Specification of Letters Patent.

Application filed September 30, 1909.

Patented Feb. '7, 1911.

Serial No. 520,280.

! through such grooves. The bridge 0 is pro vided with transverse bores (Z through each of which is passed a pin f, each end thereof being held by a screw 9 to the brace bar a in an undercut portion of the groove 0. The pins f serve the function of strengthen ing members for the brace bars a, and tend to prevent the latter from bending under strain. Only certain of the brace bars are shown as engaging the bridge; those in proximity to the bass portion of the string plate may not be extended into proximity to the bridge, and may be strengthened in any suitable manner. The string plate is provided with longitudinal strengthening bars 2' and 7a, the bar i being apertured. at Z to permit the bass strings to pass there through, and being secured to the plate by screws m.

In Fig. 3 I have shown a modified method of passing the bridge 0 through the brace bars a. The brace bar a in this form is provided with an aperture (Z the lower of the metal web a being left intact. The bridge 0 is provided with an angular bore Z) through which the edge (4 passes with out touching the bridge. The purpose and effect of the interconnection of brace bar and bridge are the same in Figs. 2 and 23, the bores (Z and Z) in each case being ust large enough to ynievent the bridge from continzting with the pin or edge a.

It will be noted from 2 and 2}, that the brace bars have been deepened or increased in width over the ordinary brace bars, in the direction of the sounding board and in this way the plane of the strings is brought to a line corresponding nearly with the center line of the brace bars so that when the strings are tcnsioned the strains will be more evenly distributed on the increased cross section of the brace bars.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. 1n pianofortes, the combination with the string plate and the brace bars thereon having grooves formed therein, of the sounding-board bridge having transverse bores and passing through the groov s in the brace bars, and strengthening member: for the brace bars connected to the latter and passing through the bores in the bridge.

2. In pianofortes, the combination with the string plate andv the brace bars thereon having grooves formed therein, of strengthening ribs carried by said brace bars in prox imity to the grooves, the sounding board bridge having transverse bores and passing through said grooves, and strengthening members for the brace bars connected to the latter and passing through the bores in the bridge.

3. In pianofortes, the combination with the soundingboard and bridge, the latter being provided with transverse bores, of the brace bars on the string plate, said brace 

